package com.demo.utils;

import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

/**
 * Redis生成唯一ID
 */
@Component
public class RedisIdWorker {

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    /**
     * 开始时间戳
     */
    private static final long BEGIN_TIMESTAMP = 1640995200L;
    /**
     * 序列号的位数
     */
    private static final long COUNT_BITS = 32;

    public long nextId(String keyPrefix){
        //1.生成时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSecond = now.toEpochSecond(ZoneOffset.UTC);
        long timeStamp = nowSecond - BEGIN_TIMESTAMP;

        //2.生成系列号
        //2.1获取当前日期 年月日 方便统计区分
        String date = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        long count = stringRedisTemplate.opsForValue().increment("icr:" + keyPrefix + ":" + date);

        //3.拼接并返回
        //将时间戳向左移动32位 序列号补位
        return timeStamp << COUNT_BITS | count;
    }

    public static void main(String[] args) {
        LocalDateTime time = LocalDateTime.of(2022, 1, 1, 0, 0, 0);
        //查看当前时间秒数
        long second = time.toEpochSecond(ZoneOffset.UTC);
        System.out.println("second:" + second);
    }
}
